Synthesis, Evaluation, and Structure-Activity Relationship Study of Lanosterol Derivatives To Reverse Mutant-Crystallin-Induced Protein Aggregation.

We describe here the development of potent synthetic analogues of the naturally occurring triterpenoid lanosterol to reverse protein aggregation in cataracts. Lanosterol showed superiority to other scaffolds in terms of efficacy and generality in previous studies. Various modified lanosterol derivatives were synthesized via modification of the side chain, ring A, ring B, and ring C. Evaluation of these synthetic analogues draws a clear picture for SAR. In particular, hydroxylation of the 25-position in the side chain profoundly improved the potency, and 2-fluorination further enhanced the biological activity. This work also revealed that synthetic lanosterol analogues could reverse multiple types of mutant-crystallin aggregates in cell models with excellent potency and efficacy. Notably, lanosterol analogues have no cytotoxicity but can improve the viability of the HLE-B3 cell line. Furthermore, representative compound 6 successfully redissolved the aggregated crystallin proteins from the amyloid-like fibrils in a concentration-dependent manner.

Pharmacological efficacy of FGF21 analogue, liraglutide and insulin glargine in treatment of type 2 diabetes.

Fibroblast growth factor 21 (FGF21) is a promising regulator of glucose and lipid metabolism with multiple beneficial effects including hypoglycemic and lipid-lowering. Previous studies have reported that FGF21 is expected to become a new drug for treatment of diabetes. Liraglutide and insulin glargine are the two representative anti-diabetic biological drugs. In the current study, we aim to compare the long-term pharmacological efficacy of mFGF21 (an FGF21 analogue), liraglutide and insulin glargine in type 2 diabetic db/db mice. Db/db mice were initially treated with three kinds of proteins (25nmol/kg/day) by subcutaneous injection once a day for 4weeks, then subsequently be treated with once every two days for next 4weeks. After 8weeks of treatments, the blood glucose levels, body weights, glycosylated hemoglobin levels, fasting insulin levels, serum lipid profiles, hepatic biochemical parameters, oral glucose tolerance tests and hepatic mRNA expression levels of several proteins (GK, G6P, GLUT-1 and GLUT-4) associated with glucose metabolism of the experimental mice were detected. Results demonstrated that three proteins could significantly decrease the fed blood glucose levels of db/db mice. After treatment for 1week, the fed blood glucose levels of db/db mice in liraglutide group were significantly lower than those in mFGF21 and insulin glargine groups. However, after 2weeks of administration, the long-lasting hypoglycemic effect of mFGF21 was superior to liraglutide and insulin glargine up to the end of the experiments. Compared with liraglutide and insulin glargine, mFGF21 significantly reduced the glycosylated hemoglobin levels and improved the ability on glycemic control, insulin resistance, serum lipid and liver function states in db/db mice after 8weeks treatments. In addition, mFGF21 regulated glucose metabolism through increasing the mRNA expression levels of GK and GLUT-1, and decreasing the mRNA expression level of G6P. But liraglutide and insulin glargine could only up-regulate the mRNA expression of GLUT-4. In summary, as a hypoglycemic drug for long-term treatment, mFGF21 has the potential to be an ideal drug candidate for the therapy of type 2 diabetes.

Rational Design of Biobetters with Enhanced Stability.

Biotherapeutics are the fastest growing class of pharmaceutical with a rapidly evolving market facing the rise of biosimilar and biobetter products. In contrast to a biosimilar, which is derived from the same gene sequence as the innovator product, a biobetter has enhanced properties, such as enhanced efficacy or reduced immunogenicity. Little work has been carried out so far to increase the intrinsic stability of biotherapeutics via sequence changes, even though, aggregation, the primary degradation pathway of proteins, leads to issues ranging from manufacturing failure to immunological response and to loss of therapeutic activity. Using our spatial aggregation propensity tool as a first step to a rational design approach to identify aggregation-prone regions, biobetters of rituximab have been produced with enhanced stability by introducing site-specific mutations. Significant stabilization against aggregation was achieved for rituximab with no decrease in its binding affinity to the antigen.

Food safety assessment of Cry8Ka5 mutant protein using Cry1Ac as a control Bt protein.

Cry8Ka5 is a mutant protein from Bacillus thuringiensis (Bt) that has been proposed for developing transgenic plants due to promising activity against coleopterans, like Anthonomus grandis (the major pest of Brazilian cotton culture). Thus, an early food safety assessment of Cry8Ka5 protein could provide valuable information to support its use as a harmless biotechnological tool. This study aimed to evaluate the food safety of Cry8Ka5 protein following the two-tiered approach, based on weights of evidence, proposed by ILSI. Cry1Ac protein was used as a control Bt protein. The history of safe use revealed no convincing hazard reports for Bt pesticides and three-domain Cry proteins. The bioinformatics analysis with the primary amino acids sequence of Cry8Ka5 showed no similarity to any known toxic, antinutritional or allergenic proteins. The mode of action of Cry proteins is well understood and their fine specificity is restricted to insects. Cry8Ka5 and Cry1Ac proteins were rapidly degraded in simulated gastric fluid, but were resistant to simulated intestinal fluid and heat treatment. The LD50 for Cry8Ka5 and Cry1Ac was >5000 mg/kg body weight when administered by gavage in mice. Thus, no expected relevant risks are associated with the consumption of Cry8Ka5 protein.

Increased aggregation of polyleucine compared with that of polyglutamine in dentatorubral-pallidoluysian atrophy protein.

Polyglutamine (polyQ) diseases result from expansion of CAG trinucleotide repeats in their responsible genes. Although gene products with polyQ expansions undergo conformational changes to aggregate in neurons, the relationship between inclusions and neurotoxicity remains unclear. Dentatorubral-pallidoluysian atrophy (DRPLA) is a polyQ disease, and DRPLA protein, also known as atrophin-1 (ATN1), carries an expanded polyQ tract. To investigate how an expanded polyQ tract influences ATN1 aggregation and localization, we compared the aggregation of ATN1 with a polyQ tract to that of ATN1 with a polyleucine (polyL) tract. In COS-7 cells, polyL-ATN1 triggered more aggregation than polyQ-ATN1 of similar repeat sizes. Immunocytochemical and biochemical studies revealed that replacement of the polyQ tract with polyL alters ATN1 localization, leading to retention of polyL-ATN1 in the cytoplasm. Despite this change in localization, polyL-ATN1 and polyQ-ATN1 demonstrate comparable repeat length dependent toxicity. These results suggest that expanded polyQ repeats in ATN1 may contribute to neurodegeneration via alterations in both protein aggregation and intracellular localization.

Evaluation of adverse effects of mutein forms of recombinant human interferon alpha-2b in female swiss webster mice.

PURPOSE: We successfully developed recombinant human interferon alpha-2b (rhIFN- α 2b) and mutein forms through the site-directed mutagenesis technique. The mutein forms were developed by substituting cysteins at positions 2 and 99 with aspartic acids. The potential adverse effects of these rhIFN- α 2bs were assessed by acute and subchronic studies. METHODS: In the acute study, rhIFN- α 2bs were subcutaneously administered to mice at a single dose of 97.5 µ g/kg, 975 µ g/kg, and 9.75 mg/kg BW and were observed for 14 days. In the subchronic study, single dose of 1.95 µ g/kg and 19.5 µ g/kg, respectively, was given subcutaneously every 3 days for 45 days. RESULTS: No death as well as abnormality in body weight, behavior, presentation of main organs, and value of plasma SGPT and SGOT was observed. Wild type and mutein rhIFN- α 2bs did not show significant adverse effects at dose up to 9.75 mg/kg BW. Administration of these rhIFN- α 2bs given repeatedly did not induce any adverse effect. CONCLUSION: These results suggest that our rhIFN- α 2bs are safe. However, further study is still needed to clarify the safety issue before use in clinical trial.

A mutated glucagon-like peptide-1 with improved glucose-lowering activity in diabetic mice.

OBJECTIVES: The aim of this study was to characterize the conformation and potency of a mutated glucagon-like peptide-1 (mGLP-1), and evaluate its glucose-lowering activity in diabetic mice. METHODS: Spectroscopy techniques were employed to characterize the conformation of mGLP-1. Glucose tolerance test was performed to determine the potency of mGLP-1 in vivo. A mouse model in which diabetes was induced by multiple low doses of streptozotocin was established to evaluate the glucose-lowering activity of mGLP-1. KEY FINDINGS: Compared with native GLP-1, mGLP-1 had a similar conformation and an enhanced potency in vivo. In diabetic mice, mGLP-1 displayed a significantly improved glucose-lowering activity as judged by fasting glucose and insulin, oral glucose tolerance test, beta cell function analysis and histochemical analysis. CONCLUSIONS: Collectively, mGLP-1 possesses an improved glucose-lowering activity in vivo and therefore can be recognized as a potential candidate for the future development of anti-diabetic drugs.

Adenovirus-mediated Drosophila melanogaster deoxyribonucleoside kinase mutants combined with gemcitabine harbor a safe cancer treatment profile.

The purpose of this analysis was to investigate the enzyme activity and specificity of adenovirus-mediated Drosophila melanogaster deoxyribonucleoside kinase (Dm-dNK) mutants in combination with gemcitabine. Compared to herpes simplex type 1 thymidine kinases (HSV-TK) and other known dNKs, this Dm-dNK enzyme has a broader substrate specificity and a higher catalytic rate. We created the Dm-dNK mutants (dNKmut) by site-directed mutagenesis at the sites of 244E, 245S, 251S, and 252R, with the last 10 amino acids in the amino acid sequence randomly alternated. We subsequently evaluated the enzyme activity and substrate specificity. The engineered enzymes showed a relative increase in phosphorylation in the nucleoside analogs of gemcitabine (dFdC, 2',2'-difluoro-deoxycytidine) compared to the wild-type enzyme. The dNKmut enzymes were expressed in breast (Bcap37) and gastric (SGC-7901) cancer cell lines. In studying the sensitivity of the cell lines to dFdC, conditionally replicative adenovirus (CRAd) ZD55-dNKmut showed higher expression and enzymatic activity than the replication-defective adenovirus Ad-dNKmut in cancer cells, but with less cytotoxicity to cancer cells than that of Ad-dNKmut. Our data suggest that the triple phosphorylated dFdC catalyzed by dNKmut inhibited the replication of adenovirus with a simultaneous positive therapeutic effect on cancer cells. Therefore, concomitant use of the ZD55-dNKmut and dFdC could be a novel targeted strategy in suicide gene therapy with safe control of excessive virus replication.

Design of second generation therapeutic recombinant bone morphogenetic proteins.

Bone morphogenetic proteins (BMPs) are growth factors belonging to the TGF beta super family. To date, more than twenty human BMPs have been identified. Of these, BMP-2 and BMP-7 (also known as osteogenic protein 1 or OP-1) are the only BMPs used clinically. Recombinant forms of both proteins are currently being implanted surgically to induce spinal fusion and to treat long bone non-union fractures. However, in both indications, large quantities of recombinant proteins are needed to induce new bone formation. This translates to higher costs and potential safety risks. Various genetic engineering approaches are being considered to produce second generation BMPs with improved safety and efficacy profiles. Modified BMPs with one or more of the following characteristics are being considered: (i) improved binding affinity to specific target cell surface BMP receptors, (ii) decreased sensitivity to natural BMP inhibitors, (iii) better immunogenicity profile, and (iv) increased solubility and stability, to cite a few. This review summarizes the progress made so far in this field and gives a perspective on what the next generation BMPs could look like.